Despite advances in surgery, chemotherapy, and radiation modalities, patients with advanced head and neck cancer continue to be at high risk for loco-regional recurrences and distant metastasis. These cancers are devastating due to their impact on multiple organ systems and quality of life. New approaches are needed to improve the care of these patients. One strategy to address these issues is dendritic cell (DC)-tumor fusion hybrid immunotherapy. A single DC-tumor fusion vaccination has been shown to mediate the regression of established tumors in mice. However, successful DC-tumor fusion immunotherapy has required the systemic co-administration of IL-12. Unfortunately, the clinical use of IL-12 is limited by toxicity. Furthermore, immune regulatory mechanisms such as regulatory T cells (Treg) may limit the full effectiveness of DC-tumor fusion-based immunotherapy. Such immune regulatory mechanisms can be overcome using anti-CTLA-4 monoclonal antibody (mAb), but systemic administration of this mAb is costly and associated with toxicity, limiting the clinical applicability of such an approach. A novel approach is proposed for the immunotherapy of head and neck cancer using DC-tumor fusions that locally deliver IL-12, as well anti-CTLA-4 mAb, to the site of DC-tumor fusion/T cell interactions. The overall objective of this application is to optimize the ability of DC-tumor fusion hybrids to induce anti-tumor responses. The central hypothesis is that DC-tumor fusion hybrids that locally secrete IL-12 will stimulate a CD4+ and CD8+ T cell mediated anti-tumor response. Furthermore, we hypothesize that the ability of these fusion hybrids to stimulate anti-tumor immunity will be enhanced by local secretion of anti-CTLA-4 mAb by the DC-tumor fusion. This central hypothesis will be tested by pursuing three specific objectives: 1) Induce anti-tumor CD4+ and CD8+ effector T cells through vaccination with DC-tumor fusion hybrids locally secreting IL-12. Murine models will be used to test the hypothesis that local secretion of IL-12 by the DC-tumor fusion will induce tumor regression via both CD4+ and CD8+ T cells; 2) Further enhance the ability of DC-tumor fusion hybrids to stimulate anti-tumor immunity by abrogating Treg-mediated immunosuppression locally. Murine models will be used to test the hypothesis that abrogating Treg immunosuppression through local delivery of anti-CTLA-4 mAb by the DC-fusion will result in enhanced anti- tumor immunity; 3) In a human in vitro model, induce anti-tumor CD4+ and CD8+ effector T cells using DC-tumor hybrids locally secreting IL-12 and anti-CTLA-4 mAb. Human in vitro models will test the hypothesis that human DC-tumor fusion hybrids secreting both IL-12 and anti-CTLA-4 mAb will potentiate the CD4+ and CD8+ T cell anti-tumor response compared with using either one alone. Dr. Walter Lee (PI) is intimately familiar with the limitations and challenges of current therapies for head and neck cancers. He has demonstrated a commitment to pursuing immunotherapy approaches to treating these cancers and has focused his work on dendritic cell (DC) - tumor fusion hybrids. He has assembled well qualified mentors and consultants to further his development as a surgeon-scientist focused on DC-tumor fusion immunotherapy. Dr. Lee's career development plan includes didactic courses and seminars that are integrated into his laboratory learning objectives. He will also be mentored in the design, execution, and data analysis of clinical trials that involve DC-tumor fusion hybrids and other immunotherapy approaches. Through this VA Career Development Award-2 (VA-CDA-2), Dr. Lee will elucidate mechanisms that influence successful DC-tumor fusion as well as obtain the skills needed to move laboratory findings to clinical trials. Furthermore, this VA-CDA-2 will allow Dr. Lee to establish a VA-based career and enable him to mature into an independently funded surgeon scientist.